John Thompson, an arborist, bonsai enthusiast, and oak specialist who has worked with trees since the ’80s, gave the Marin Bonsai Club its first oak demonstration in eight years this October, and it was well worth the wait.
John was kind enough to provide everybody in the audience with a cardstock copy of what he calls his “Toolbox,” a copy of which is included here. John said he has developed this “cheat-sheet” of sorts throughout his time as a bonsai enthusiast and always refers back to it when in doubt regarding what needs to be done next with a particular tree. He invites and encourages us to do the same. Much of what is there will be familiar to anyone who has attended past Marin Bonsai lectures by Peter Tea or Jonas Dupuich. As John proceeded, he loosely followed the outline of his Toolbox.
As he began to thin branches on the demo tree, John pointed out more of the features of his Toolbox handout. The far right of the handout outlines important dates for timing various types of tree work, including some general reminders about pinching and wiring. The middle part of the handout covers all the different types of tree manipulations, the part that is most like Peter Tea’s keystone summary of the different types of manipulation. John nicely divides them into those methods that affect the whole tree and those we use to work on specific, targeted areas.
While introducing two of the three trees he brought, all valley oaks, John talked a bit about all the different varieties of oak available in California and some of the ways oaks are unique. He pointed out that while conifer branches initially tend to point downward and deciduous branches tend to point upward, oaks are different because their branches can go all over, as anyone who has driven on Highway 101 between Novato and Petaluma knows. Oaks also tend to be wider than they are tall. All these factors must be considered to produce a realistic likeness in an oak bonsai.
An interesting side note John made involved collecting cork bark oaks (one of his favorites!) from wine vintners, who use them to make . . . you guessed it, corks. John emphasized how important it is to get trees that have been discarded in their first ten years of life. That’s because the vintners like their bark straight and less gnarled by branch growth and such. To get them that way, they strip all the original bark and lower branches after ten years of growth, so that what grows back is less gnarled and more conducive to compact, straight-grained corks. Definitely not a good look for bonsai, though!
The third tree John brought with him was the demo tree, one he purchased from a Calaveras nursery almost a year prior. He put its age at about 8 to 9 years old. As he began to assess the tree to determine where to start working on it, he drew our attention to the top left side of his Toolbox handout, where it outlines the stages of work that can be done to a tree. Peter Tea fans will recognize the priority: The trunk is always considered first. Only once that is close to where it needs to be can we start thinking about how to make the primary branches better, then secondary branches, and so forth. Failing to follow this priority can lead to wasted work done prematurely on areas that will end up having to be chopped off to correct a higher priority area. John already knew that the tree had a good trunk, that’s why he chose it, so he proceeded to choose the primary branches so he could begin to thin the others away. He also acknowledged that we need to choose a front for the tree, but moved on without involving the audience in that decision.
As his work on the demo tree progressed, John continued to give general bonsai and specific oak tips. He said that knowing your tree type is important for knowing what you can do to it. Not just knowing things like the fact that deciduous trees are hardwood and cannot be bent as easily as conifers, like pines and junipers. You also should try to get to know the specific characteristics of the species you’re working on so that you can emulate them in your design, like the fact that the interior growth areas of white oaks tend to be bare.
While assessing the demo tree and contemplating what to do with the bushy top, John reiterated a point we have learned many times over from Peter Tea, which is that balancing the energy of a bonsai often means close-cropping the top and letting the bottom branches go for awhile. As a counterpoint, he also pointed out that in nature, older deciduous and evergreen trees are more rounded on top, whereas younger trees are pointier, so to depict age in our bonsai, we should develop a full canopy. Choosing the correct approach for the demo tree proved a little tricky, since its canopy was somewhat divided into a few separate rounded crowns. Rather than sacrifice any of the tops, John decided to trim a little heavier (creating shorter branches) between the different crowned sections, to help differentiate them. That would allow the winner of the tree to develop all of those tops, either for later selection of the apex, or to induce ramification in order to combine all the tops into one canopy, all while satisfying the need to encourage energy redistribution to the lower parts of the tree.
So John trimmed the multiple crowns pretty short, to keep them suppressed. While doing that, he reminded us to cut back shorter than what we actually want when doing major pruning, to leave room for branch division and ramification out to the point where we want our final tree outline to be. In the end, the demo tree was encouraged to grow outward more, upward less. Not too much was trimmed off, so this tree could be repotted this coming spring. John finished with a quick description of how that process should proceed for an oak recently purchased from a nursery. He said he usually begins by chopping off the bottom half of the existing nursery soil. Then, next repotting, only replace half of the soil, horizontally. Two years later, clear and replace the other half, similar to how we repot pines.
The demo tree was won by Chris Ross, who promised to show us the tree’s progress at later club meetings.
– David Eichhorn